A polyolefin resin has a problem that, for example, it has an insufficient adhesiveness, coating property and printing property with an inorganic material or a metal.
In order to solve said problem, there is generally known a method of melt-kneading in an extruder a polyolefin resin, an epoxy group-carrying derivative and a radical-generating compound.
However, said method has a limit for raising a graft amount, because adding a large amount of the radical-generating compound results in a remarkable change of a melt index (MI) of a melt-kneading product.
In order to solve said problem, there are known (1) a method of adding styrene (“Design of Practical Polymer Alloy”, page 51, written by Fumio Ide and published by Kogyo Chosakai (1996)), and (2) a method of adding divinylbenzene (JP-A-7-173229). However, both of these methods do not give a satisfactory result.